Recently, a system for automating a production process by making a robot to do various works which were conventionally performed by a worker is broadly made practicable (Patent document 1).
For example, in a work for mounting a relatively heavy apparatus to a given position in a product in production, conventionally the apparatus is lifted by a hoist or the like and a worker moves it to a given position and fixes the apparatus to the product in production by a bolt or the like, while there is a system to make a robot to do this conveyance work of the apparatus instead.
Now, when mounting a motor to the product in production, there are cases when the state of the motor needs to be changed in order to perform the mounting work without hindrance. For example, when the product in production is a robot (hereunder, the robot to be produced is referred to as “product robot”), and a servo motor for driving an arm of the product robot is mounted to a given position of the product robot using a robot for work (hereunder, the working robot used for producing the product robot is referred to as “work robot”), there are cases when an electromagnetic brake of the servo motor needs to be temporarily un-locked.
Thus, in the product robot to which the servo motor is fixed by the fixing bolt, when the servo motor is conveyed by the work robot and it is mounted to a drive shaft of the product robot, the fixing bolt needs to be inserted into a screw hole by inserting an output shaft of the servo motor into an insertion hole provided on the product robot side so as to make a gear on the drive shaft side and a gear on a distal end of the output shaft to engage with each other, and also rotating the motor body about an axis of the output shaft so as to position a screw hole provided on the product robot body side and a hole for the fixing bolt provided on the motor body side.
However, in the servo motor to be mounted to the drive shaft of the product robot, generally a non-exciting operation type electromagnetic brake is provided in order to prevent runaway of the robot at the loss of the power source and falling-off of objects to be conveyed.
When a servo motor with such non-exciting operation type electromagnetic brake is mounted to the drive shaft of the product robot, the motor output shaft is fixed or restrained to the motor main body and cannot be rotated, since power supply is not supplied to the servo motor.
Accordingly, when the output shaft of the servo motor with the non-exciting operation type electromagnetic brake is inserted into a hole provided on the drive shaft side of the product robot and the gear on the drive shaft side and the gear on the motor output shaft side are engaged with each other, the motor main body cannot be rotated and the position of its fixing bolt hole cannot be positioned to the screw hole on the robot side, since the motor output shaft and the motor main body are restrained.
Therefore, when performing work for mounting the servo motor with the non-exciting operation type electromagnetic brake to the drive shaft of the product robot, it is necessary to actuate the electromagnetic brake until the output shaft of the servo motor is inserted into the hole provided on the robot drive shaft side and the gear on the drive shaft side and the gear on the motor output shaft side are engaged with each other, and un-lock the electromagnetic brake after the gear on the drive shaft side and the gear on the motor output shaft side are engaged with each other so that the motor main body can be rotated about the motor output shaft.
Note that, when a worker mounts the servo motor as in a conventional manner, the attitude of the product robot (angle of the robot arm, or the like) can be changed more or less in production. Therefore, the position of the fixing bolt hole of the motor main body can be aligned to the position of the screw hole on the robot side by changing the attitude of the product robot more or less in the state that the gear on the drive shaft side of the product robot and the gear on the motor output shaft side are engaged with each other.
In contrast, when the product robot is produced using the work robot, the attitude of the product robot in production is firmly fixed since parts such as the motor need to be mounted to a previously taught position. Therefore, the position of the fixing bolt hole on the motor main body side and the position of the screw hole on the robot side cannot be aligned to each other by changing the attitude of the product robot in the state that the gear on the drive shaft side of the product robot and the gear on the motor output shaft side are engaged with each other.
Moreover, even when the object to which the motor is mounted by the work robot is another product not the product robot, the motor main body cannot be rotated in the state that the gear on the product side and the gear on the motor output shaft side are engaged with each other unless the brake of the motor is un-locked, when the gear on the product side is in a fixed state.
Moreover, there are cases when the electric apparatus need to be operated so as to change its state in the middle of conveyance/mounting work by the work robot even when the object to be conveyed by the work robot is an electric apparatus other than the motor. However, the conventional technique cannot respond to such demand.